There are many different sun visors. They are generally formed of many separate parts, making them relatively expensive to construct and tedious to install. Most known visors are installed by being screwed into place. For example, the bearing housings are generally screwed to the roof frame of the vehicle. Also, known sun visors often are not safe, as some of their parts are made of metal. This is true of the bearing axles and generally also of the bearing housings.